Preparation of electromagnetic shielding wood-metal composite by electroless nickel plating

Electrical and electromagnetic shielding wood metal composite was prepared by using electroless nickel plating. The effects of solution amount, plating time and plating temperature on surface resistivity and electromagnetic shielding effectiveness were investigated. And P content, microstructure and surface feature of layers obtained at different temperatures were analyzed by energy dispersion spectrometer （EDS）, X-ray diffraction （XRI）） and scanning electron microscopy （SEM）. The results showed that layers with higher electro-conductivity and electromagnetic shielding effectiveness were obtained under the optimum conditions that plating solution was 500 mL, plating time was 30 min and plating temperature was 62℃. The results showed by EDS analysis; that P content increased gradually in a small extent with plating temperature increased. It was showed by XRD and SEM analysis that layers plated at different temperatures were all microcrystalline structure and uniform and successive, which had noticeable metal luster. Those indicated that plating temperature had little influence on microstructure and surface feature under pH value invariable.

Copper-Ti_3SiC_2 composite powder prepared by electroless plating under ultrasonic environment

In this article, a new type of Cu-Ti3SiC2 composite powder prepared using the electroless plating technique was introduced. The initial Ti3SiC2 particles are 11 μm in diameter on an average. The Cu plating was carried out at middle temperature （62-65℃） with the application of ultrasonic agitation. The copper deposition rate was determined by measuring the weight gain of the powder after plating. It has been found that the pretreatment of Ti3SiC2 powder is very important to obtain copper nanoparticles on the surface of Ti3SiC2 The optimum procedure before plating aimed to add activated sites and the adjustment of the traditional composition of the electroless copper plating bath could decelerate the copper deposition rate to 0.8 gm/h. X-ray diffraction （XRD） indicates that the chemical composition of the plating layer is copper. SEM images show that the surface of the Ti3SiC2 particles is successfully coated with continuous copper layer. The wetting property between the copper matrix and Ti3SiC2 can be improved so as to increase the interfacial strength.

The study of electroless Ni-W-P alloy plating on glass fibers

Ni-W-P coatings were deposited on the surface of glass fibers by the electroless plating process. The bath was very stable through the palladium salt test. There was no phenomenon of peeling and blistering on the surface of the Ni-W-P alloy glass fibers in the thermal shock test. It showed that the deposit had high impact strength and good adhesion. The morphology of the coatings was observed by scanning electron microscope （SEM）. The elements and their contents were tested and analyzed by energy dispersion spectrometer （EDS）. The tungsten content reached up to 12.1 wt.%. The effects of the concentrations of NiSO4, Na2WO4, and NaH2PO2.H20 on the conductivity of the coatings were studied. The resistivity of the Ni-W-P alloy glass fibers reached 7.39 × 10^-3 Ωcm. The alloy coatings on glass fibers were analyzed by XRD. The results indicated that the deposit had an amorphous structure and good heat stability. The suitable work temperature range was lower than 190℃. Finally, the electromagnetic parameters of the Ni-W-P alloy glass fibers were tested and analyzed primarily. The magnetic loss reached 0.04023 and the dielectric loss reached -5.80239. The plated alloy is a kind of soft magnetic material.

Surface characteristics of electroless nickel plated electromagnetic shielding wood veneer

Wood is a kind of porous natural material with very poor electro-conductivity, and it has almost no function of electromagnetic shielding. The method of electroless nickel plating was used to produce wooden material with electrical and effective electromagnetic shielding properties. Ni-P alloy layer was obtained on wood surface. The surface feature of plated wood veneer was observed by SEM and the surface composition and microstructure of the layer under different conditions were investigated by EDS and XRD respectively. Meanwhile, the relevant surface resistivity and electromagnetic shielding effectiveness were measured. Correlations of the phosphorous content in the layer to the structure of Ni-P alloy, electro-conductivity and electromagnetic shielding of plated veneers were discussed. SEM photos showed that the surface of electroless nickel plated veneers were covered with Ni-P alloy layer entirely, which made wood veneers more like metal. At the same time, the results showed that with the decreasing of the phosphorous content in the layer, the microstructure of Ni-P alloy layer transformed to be microcrystalline and electro-conductivity and electromagnetic shielding effectiveness were improved. When the phosphorous content was less than 2.37wt pct in the layer, the microstructure of Ni-P alloy layer was microcrystalline structure and its sur- face resistivity and electromagnetic shielding effectiveness were nearly 0.5Ω/□ and 55-60dB respectively.

Electroless Nickel Plating and Electroplating on FBG Temperature Sensor

Metal-coated fiber Bragg grating（FBG）temperature sensors were prepared via electroless nickel（EN）plating and tin electroplating methods on the surface of normal bare FBG.The surface morphologies of the metal-coated layers were observed under a metallographic microscope.The effects of pretreatment sequence,pH value of EN plating solution and current density of electroplating on the performance of the metal-coated layers were analyzed.Meanwhile, the Bragg wavelength shift induced by temperature was monitored by an optical spectrum analyzer.Sensitivity of the metal-coated FBG（MFBG）sensor was almost two times that of normal bare FBG sensor.The measuring temperature of the MFBG sensor could be up to 280℃,which was much better than that of conventional FBG sensor.

Study on Physical and Chemical Behaviors of Rare Earths in Preparing Ceramic Tube Supported Palladium Film by Electroless Plating

The rare earths of ytterbium, lanthanum, praseodymium, neodymium and their binary mixtures were respectively added into the traditional electroless plating solution to prepare thin palladium film on the inner surface of porous ceramic tube. The experimental results shows that the addition of rare earths increases palladium deposition rates and the binary mixtures are superior to the single rare earths and the mixture of ytterbium-lanthanum is the most efficient. Adding the mixture of ytterbium-lanthanum can also reduce the plating temperature by 10 ~ 20℃, shrink the metal crystal size and improve the film densification compared to those by traditional electroless plating. A thin palladium film with 5μm was prepared and the film made a highly pure hydrogen with a molar fraction of more than 99.97% from a H2-N2 gas mixture. More attentions were paid to analyze the physical and chemical behaviors of the rare earths in palladium film preparation.

Effect of Heat Treatment on Structure and Magnetic Performance of Ni-Fe-P Alloy Obtained by Electroless Plating

The electroless deposition of Ni68-Fe10.5-P21.5 alloy has been investigated. The crystallization behavior of the deposit was comparatively studied by using differential scanning calorimetry and X-ray diffractometry. The deposit transforms into a square Ni3P phase at 380. 0 ℃, then changes into a cubic FeNi3 phase at 490. 0 ℃. The microhardness, the size of the formed grains and the magnetic performance of the deposit increase with the increase of the heat treatment temperature below 500 ℃, then they decrease after this temperature. The effect of heat treatment time at 500 ℃ on the surface micromorphology, the structure and the magnetic performance of the deposit were also studied. The resuits show that with the increase of heat treatment time, the extent of crystallization of the deposit increases and the size of the formed grains becomes uniform. The results also show that the magnetic performance of the deposit under heat treatment for 40 min is maximal and then decreases with the increase of heat treatment time. The property change of the deposit is related to the crystal structure and the size of the formed grains of the deposit.

Preparation and characterization of molybdenum powders with copper coating by the electroless plating technique

Molybdenum powders with a diameter of approximately 3 μn were coated with copper using the electroless plating technique in the pH 12.5-13 and temperature range of 55-75℃. The optimization of the electroless copper bath was evaluated through the combination of process parameters like pH and temperature. The optimized values ofpH and temperature were found to be 12.5 and 60℃, respectively, which attributes to the bright maroon color of the coating with an increase in weight of 46%. The uncoated and coated powders were subjected to microstructural studies using scanning electron microscope （SEM） and the phases were analyzed using X-my diffrction （XRD）. An attempt was made to understand the growth mechanism of the coating. The diffusion-shrinkage autocatalytic model was suggested for copper growth on the molybdenum surface.

Electroless copper plating on microcellular polyurethane foam

In order to obtain substrates with good conductive foam for high porosity foam metal materials used in the metal electrodes,the technique of electroless copper plating on the microcellular polyurethane foam with pore size of 0.3 mm was investigated.The main factors affecting the deposition rate such as the solution composition,temperature,pH value and adding ultrasonic were explored.The results show that the optimum process conditions are CuSO4 16 g/L,HCHO 5 mL/L,NaKC4H4O6 30 g/L,Na2EDTA 20 g/L,K4Fe(CN)6 25 mg/L,pH value of 12.5-13.0 and temperature of 40-50℃.Under these technical conditions, the process has excellent bath stability.Adding ultrasonic on the process can elevate the deposition rate of copper by 20%-30%.The foam metal material with a porosity of 92.2%and a three-dimensional network structure,was fabricated by electro-deposition after the electroless copper plating.

Characterization and Properties of Electroless Nickel Plated Poly (ethylene terephthalate) Nonwoven Fabric Enhanced by Dielectric Barrier Discharge Plasma Pretreatment

In order to develop a more economical pretreatment method for electroless nickel plating, a dielectric barrier discharge （DBD） plasma at atmospheric pressure was used to improve the hydrophilicity and adhesion of poly （ethylene terephthalate） （PET） nonwoven fabric. The properties of the PET nonwoven fabric including its liquid absorptive capacity （WA）, aging behavior, surface chemical composition, morphology of the surface, adhesion strength, surface electrical resistivity and electromagnetic interference （EMI）- shielding effectiveness （SE） were studied. The liquid absorptive capacity （WA） increased due to the incorporation of oxygen-containing and nitrogen-containing functional groups on the surface of PET nonwoven fabric after DBD airplasma treatment. The surface morphology of the nonwoven fibers became rougher after plasma treatment. Therefore, the surface was more prone to absorb tin sensitizer and palladium catalyst to form an active layer for the deposition of electroless nickel. SEM and X-ray diffraction （XRD） measurements indicated that a uniform coating of nickel was formed on the PET nonwoven fabric. The average EMI-SE of Ni-plating of PET nonwoven fabric maintained a relatively stable value （38.2 dB to 37.3 dB） in a frequency range of 50 MHz to 1500 MHz. It is concluded that DBD is feasible for pretreatment of nonwoven fabric for electroless nickel plating to prepare functional material with good EMI-SE properties.

Enhanced Thermoelectric and Mechanical Properties of n-type Bi2Te2.7Se0.3 Bulk Alloys by Electroless Plating with Cu

Bi2Te2.7Se0.3/Cu core/shell powders were prepared by electroless plating and hydrogen reduction, and then sintered into bulk by spark plasma sintering in order to improve the thermoelectric and mechanical properties of n-type Bi-Te thermoelectric material. After electroless plating, with the increasing of Cu content, Seebeck coefficient keeps increasing and power factor enhances significantly. The highest power factor increases by three times and reaches 23.8 W·cm^-1·K^-2 at room temperature in Bi2Te2.7Se0.3 with 0.22 wt%Cu sample, which means electrical transport properties of Bi2Te2.7Se0.3/Cu samples have been improved.Meanwhile, the ZT values of Bi2Te2.7Se0.3/Cu samples can be enhanced at different temperature zone by adjusting the Cu content. Bi2Te2.7Se0.3 with 0.05 wt% Cu sample has the best thermoelectric properties in high temperature zone, and the ZT peak value increases from 0.35 to 0.85 at 623 K. When the Cu content increases to 0.15 wt%,the ZT peak value moves to the low temperature(373 K) and increases from 0.24 to 0.71. At the same time, the mechanical properties increases with the increasing of Cu content.

Removal of nickel from spent electroless nickel-plating bath with nickel foam cathode

The electrochemical method was used to remove nickel ion from spent electroless nickel plating bath (pH=5 3). An electrolytic cell was composed of a porous nickel foam cathode and an inert RuO 2/Ti anode. Nickel ions were reduced and deposited on the surface of the nickel foam cathode. The effect of current density (i), linear velocity of wastewater(v), gap between cathode and anode(d C/A) and reaction time(t) on nickel removal rate and current efficiency were studied. As reaction time prolonged, nickel removal rate increased while current efficiency decreased. And larger v and smaller d C/A can enhance nickel removal rate and increase current efficiency by promoting mass transfer and dropping concentration polarization. The effect of current density on nickel removal by electrochemistry was related to other parameters. After three hours’ electrolysis with i=1 0 A/dm2, v=18 5 cm/min and d C/A=0 5 cm, nickel removal rate and current efficiency reached 85 6% and 29 1%, respectively.

Effects of Binary Mixture of Yb_2O_3-La_2O_3 on Pd/Ag Co-Deposition by Electroless Plating

The binary mixture of Yb2O3-La2O3 was used as an additive to improve the traditional electroless plating for Pd-Ag co-deposition on the inside surface of a porous ceramic tube. The main attention were paid to investigating the effects of Yb2O3-La2O3 on Pd-Ag co-deposition rate, plating temperature, Ag content in film and Pd/Ag reduction potentials. The experimental results show that the co-deposition rate is increased by 63 % , the plating temperature is decreased by 10 ~ 20℃for obtaining the same co-deposition rate and the Ag content in film basically remains unchangeable when Yb2O3-La2O3 is added into the traditional electroless plating solution. The experiment also shows that Pd/Ag reduction potentials basically remain unchangeable with the binary rare earths based on the electrochemical mathematical models An inorganic composite membrane with alloy film of 76.8(mol)% Pd-23.2(mol) % Ag and the thickness of 7.7μm on the porous ceramic tube was prepared and the permeation fluxes of hydrogen and nitrogen through the membrane are 8.65×10-3 and 1.92×10-6m3·m-2·s-1 at 350℃and 0.3 MPa respectively.

PRIMARY STUDY FOR THE TECHNOLOGY OF ELECTROLESS PLATING Fe-Al-P ALLOYS

Manuscript received 24 June 1999 The Fe Al P alloy deposits were plated on copper sheets by electroless plating. The change law of the deposition rate, composition, surface appearance and structure for the deposits was studied by changing the metallic salt ratios (AlCl 3/AlCl 3+FeSO 4), the concentration of metallic salt AlCl 3 and reductant NaH 2PO 2. The optimum plating bath was obtained. It was found that the choices of ligand and reductant were the key of increasing Al content for the deposits.

PROCESS AND PROPERTIES OF ELECTROLESS PLATING RE-Ni-B-SiC COMPOSITE COATINGS

Technology and properties of electroless composite RE-Ni-B-SiC coatings have been investigated.Results show that stabilizer plys a decisive role in electroless composite Ni-B-SiC,the addition of appropriate quantity of RE(rare earth) into the Ni-B-SiC bath not only increases SiC content in composite coatings,their hardness and wear resistance but also improves crystalline fineness,Wear resistance increases with the increase of SiC.Hardness and wear resistance of composite coatings reach peak values a fter heat treatment at 4OO and 500℃ for 1h respectively.

Synthesis and microwave characterization of Co-SiC core-shell powders by electroless plating

Co-SiC core-shell powders were prepared by electroless plating. Scanning electron microscopy （SEM） revealed that Co-SiC core-shell powders were of nearly sphere-like shape and were about 0.3 pan. X-ray powder diffraction （XRD） patterns showed that the cobalt powder was hexagonal crystallite. The complex dielectric constant and the complex permeability of Co-SiC core-shell powders-paraffin wax composite were measured by the rectangle wavegnide method. It showed that the dielectric loss was less than 0.1 and the magnetic loss was about 0.2 in 8.2-12.4 GHz for prepared Co-SiC core-shell comoosite oowders.

STUDY ON UNIFORMITY OF ELECTROLESS PLATING SOLUTION OF SOLAR CONTROL GLASS

A new type elctroless plating bath for solar control glass with large area uniform plating was presented on the basis of the relative Reynolds numbers , the temperature distribution calculation and the relative structure design. The experimental data of the distribution and change of temperature indicate that the mass transfer of the fluid was steady laminar flow and the difference of the maximum temperature was less than 0 5℃ in glass dipping region of 1000×200×1000mm.

A New Activation Method for Electroless Metal Plating: Palladium Laden via Bonding with Self-Assembly Monolayers

A new activation method has been developed for electroless copper plating on silicon wafer based on palladium chemisorption on SAMs of APTS without SnCl2 sensitization and roughening condition. A closely packed electroless copper film with strong adhesion is successfully formed by AFM observation. XPS study indicates that palladium chemisorption occurred via palladium chloride bonding to the pendant amino group of the SAMs.

Wear and Corrosion Resistance of Electroless Plating Ni-P Coating on P110 Steel

In order to improve the surface performance and increase the lifetime of P 110 oil casing tube steel during operation, electroless plating was conducted to form Ni-P coating onto its surface. The surface morphology/element distribution and phase constitution of the Ni-P coating were analyzed using scanning electron microscope （SEM） equipped with energy dispersive spectrometry （EDS） and X-ray diffraction （XRD）. Tribological and electrochemical measurement tests were applied to investigate the wear and corrosion resistance of P110 steel and the Ni-P coating. The results showed that a uniform and compact, high phosphorous Ni-P coating was formed. The obtained Ni-P coating indicated certain friction-reduction effect and lower mass loss during friction-wear tests. The Ni-P coating also exhibited higher corrosion resistance in comparison with bared P 110 steel. The obtained N i-P coating has significantly improved the surface performance of P110 steel.